Five things to learn first, in this order: (1) what an option actually is, (2) calls vs puts, (3) delta (the only Greek that matters at first), (4) how time decay (theta) works, (5) the cash-secured put — your first sensible trade. Skip to strategy #6 or the Greeks pages only after these five are second nature. Most UK retail losses come from skipping ahead.
1. What an option actually is
An option is a contract that gives you the right but not the obligation to buy or sell something at a specific price (the strike) by a specific date (expiration). You pay a premium to the seller for that right.
Key analogy: think of a deposit on a house. You pay £1,000 for the option to buy the house at £300,000 within 30 days. If house prices spike to £350,000, you exercise (buy at £300,000 and sell at £350,000 — £49,000 profit). If house prices fall to £280,000, you walk away — you lose only the £1,000 deposit. Options work the same way on shares.
One option contract = 100 shares (almost always — check on UK-listed contracts which can be different). So a £1.50 call premium = £150 cost per contract (£1.50 × 100).
2. Calls vs puts
- Call option: right to BUY the underlying at the strike. Bullish bet (you profit if the stock rises).
- Put option: right to SELL the underlying at the strike. Bearish bet (you profit if the stock falls) OR insurance on shares you own.
For every option there's a buyer and a seller. The buyer pays premium for the right. The seller (writer) collects premium and takes on the obligation. As a beginner, only buy options for the first 6 months — never sell ("write") naked options. The risk is unlimited.
3. Delta — the only Greek that matters at first
Delta is how much the option price moves for each £1 move in the underlying.
- Delta of 0.50 = option moves 50p for every £1 the stock moves.
- At-the-money options (strike near current price) have delta around 0.50.
- Deep in-the-money calls have delta near 1.00 (move like the stock itself).
- Deep out-of-the-money calls have delta near 0.00 (almost no movement).
Delta is also a rough proxy for "probability of finishing in the money" — a 0.30 delta call has roughly a 30% chance of finishing profitable. Useful mental model.
Other Greeks (gamma, theta, vega, rho) matter eventually. For your first 10 trades, just track delta.
4. How time decay (theta) works
An option is wasting asset — it loses value as expiration approaches, even if the underlying doesn't move. This is "theta decay."
- A 30-day option loses very little value day 1. It loses dramatic value in the final week.
- Theta is the dollar amount the option loses per day. A theta of −0.05 = the option loses 5p of value per day.
- Short-dated options (7-14 days) have the highest theta — fastest decay.
- Long-dated options (3+ months) have low theta — slow decay.
For beginners, this means: don't buy options that expire in 1-7 days unless you're sure of the move. The decay will kill you. Stick to 30-60 day expirations until you understand IV crush.
5. The cash-secured put — your first sensible trade
The single best beginner strategy is the cash-secured put. Mechanics:
- Choose a high-quality stock you'd be happy to OWN at a discount.
- Sell a put option at a strike BELOW the current price (typically 5-10% below).
- You collect a premium upfront.
- You hold the cash needed to buy at the strike (that's why it's "cash-secured").
Two outcomes:
- Stock stays above strike at expiration: the put expires worthless. You keep the full premium. Repeat next month.
- Stock falls below strike at expiration: you're assigned the shares (you buy them at the strike). You wanted them anyway. Your effective purchase price is strike minus premium received.
Both outcomes are acceptable. You either earn income or buy shares at a discount. Cash-secured puts on quality companies are the foundation of most retail options income strategies.
Common beginner mistakes
- Buying 7-day OTM options. Theta destroys these. Most lose 100% of their premium.
- Selling naked calls. Theoretical maximum loss is unlimited. Don't.
- Trading earnings. Implied volatility crushes after earnings — even if your directional bet was right, you can lose money. See the earnings + IV crush guide.
- Trading meme stocks. The implied volatility is gambling-grade. Stick to large-cap quality (£10bn+ market cap) for your first 6 months.
- Position-sizing too large. Risking more than 2-5% of your portfolio on a single options trade is portfolio-killing. See position sizing guide.
What to read next
- The full Greeks page — when you're ready for gamma, vega, rho.
- Options income strategies — once cash-secured puts are routine, learn covered calls and wheel strategy.
- Defined-risk strategies — credit spreads, iron condors. Higher complexity.
- Black-Scholes options calculator — pricing intuition.
- UK tax + platforms guide — the regulatory wrapper.
Sources and methodology
This page is educational only and not financial advice. Options carry the risk of losing your entire premium and (when selling) potentially unlimited loss. The full UK Tax Drag options reference is in the options trading guide. For regulated investment advice, consult an FCA-authorised IFA — see the tax adviser editorial recommendation. The methodology page documents sources.
Related options guides
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